Padma,
I've removed the con.close() method from getResultSet() and i also removed the close() call from my jsp,which calls the close() method in the calling class,which calls the close() method in this class.
Whatever be the case, second time you dont seem to have a valid handle to datasource, and the line results = st.executeQuery(Query); runs irrespective of state of data source.
You will have to handle the case if ds is null, if so you have to call getResults() to get data source
I think ,this might be the error,can you please tell me how to handle this??